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    <p>I started to fix this code but soon realized there is so much wrong in it, I don't know where to start. So instead, this turned out to be a <a href="https://codereview.stackexchange.com/">code review</a> answer instead, I apologize up front if it is detailed and picky.</p> <ul> <li><p>There's a rule of thumb in C saying that if you need more than two levels of pointer indirection, your code is obfuscated and should be rewritten (reference MISRA-C:2004 17.5).</p></li> <li><p>It doesn't make sense whatsoever to use dynamic memory allocation in this case, because you already know at program start-up that no string will be larger than 11 characters and there will not be more than 30 strings. If this condition is not true, you need to write a safer input method, preferably with fgets() which is safe against buffer overflows. Make sure that the input doesn't go out of bounds of array "Cod". You can allocate 30*11=330 bytes statically without a guilty conscience. And it will make the code faster.</p></li> <li><p>It doesn't make sense to have 3 levels of indirection for an array of strings. You aren't even using the dynamic memory to hold a copy of strings, you just allocate pointers. This doesn't make any sense at all. If you need a pointer lookup table pointing at <code>Cod</code> then allocate it statically, it will only require sizeof(char*)*30 bytes. </p></li> <li><p>As already mentioned, you can only use realloc on a pointer that has previously been malloc/calloc:ed.</p></li> <li><p>As already mentioned, never typecast the result of malloc/realloc in C. This is C++ practice. In C, it destroys type safety and hides type compatibility bugs. There are countless, detailed discussions about this here on SO if you want to know the details.</p></li> <li><p>What if you don't find "p" in the user string? The program will go havoc.</p></li> <li><p>Don't name variables that affect fundamental program functionality to abstract things like tmp, vec etc. tmp could be renamed to input_buf or something, etc.</p></li> <li><p>Avoid magic numbers in code, use const or #define for array length constants.</p></li> <li><p>You can initialize strings in C, there is no need for strcpy to do so. <code>char input_buf[INP_BUF_N] = "p";</code></p></li> <li><p>To search for a char in a string, use strchr().</p></li> <li><p>You shouldn't need to have the user inputting the same thing twice with scanf() in the outer do-while loop, likely a typo bug.</p></li> <li><p>You can not do wild typecast between a static array of arrays to a pointer-to-pointer. This depends on the structure of whatever the pointer-to-pointer points at. Because a typical dumb-school-book dynamic 2D-array (malloc(X<em>sizeof(char</em>)... malloc(Y*sizeof(char)) will not allocate memory adjacently. Plenty of discussions about this here on SO.</p></li> </ul> <p>(you can allocate dynamic 2D arrays in adjacent memory with the use of array pointers or with "mangling", but those are rather advanced topics)</p> <ul> <li>free() the dynamic memory once you are done using it.</li> </ul> <p>As you hopefully can tell, the wise choice here is to rewrite this code from scratch.</p>
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    1. CO+1 ... MISRA 17.5, apparently, is an advisory rule; not a "rule of thumb" ;)
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    2. COThanks for the reply and for the advice. Well I really have to make dynamic because I have a limit of 30 strings in the array (cod) but I don't know many "30 strings limit" I will have. I need to save a string with limit of 11 chars in an array with limit 30. Than I need to save that array in the first position of a new one... and so one.... <br> <br> The do while cycle is working, I already tested it. The error is in the allocation of memory. The cod array is working also, the problem is the dynamic array (vec).
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    3. CO@pmg Yes I know, I merely wanted to cite an authority so that people don't think these are just my own personal opinions.
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